ingress-nginx Exposing TCP and UDP services

墨蓝 2022-03-21 15:40 162阅读 0赞

Ingress does not support TCP or UDP services. For this reason this Ingress controller uses the flags `--tcp-services-configmap`and `--udp-services-configmap` to point to an existing config map where the key is the external port to use and the value indicates the service to expose using the format: `<namespace/service name>:<service port>:[PROXY]:[PROXY]`

It is also possible to use a number or the name of the port. The two last fields are optional. Adding `PROXY` in either or both of the two last fields we can use Proxy Protocol decoding (listen) and/or encoding (proxy\_pass) in a TCP service [https://www.nginx.com/resources/admin-guide/proxy-protocol][https_www.nginx.com_resources_admin-guide_proxy-protocol]

The next example shows how to expose the service `example-go` running in the namespace `default` in the port `8080` using the port `9000`

apiVersion: v1
    kind: ConfigMap
    metadata:
      name: tcp-services
      namespace: ingress-nginx
    data:
      9000: "default/example-go:8080"

Since 1.9.13 NGINX provides [UDP Load Balancing][]. The next example shows how to expose the service `kube-dns` running in the namespace `kube-system` in the port `53` using the port `53`

apiVersion: v1
    kind: ConfigMap
    metadata:
      name: udp-services
      namespace: ingress-nginx
    data:
      53: "kube-system/kube-dns:53"

If TCP/UDP proxy support is used, then those ports need to be exposed in the Service defined for the Ingress.

apiVersion: v1
    kind: Service
    metadata:
      name: ingress-nginx
      namespace: ingress-nginx
      labels:
        app.kubernetes.io/name: ingress-nginx
        app.kubernetes.io/part-of: ingress-nginx
    spec:
      type: LoadBalancer
      ports:
        - name: http
          port: 80
          targetPort: 80
          protocol: TCP
        - name: https
          port: 443
          targetPort: 443
          protocol: TCP
        - name: proxied-tcp-9000
          port: 9000
          targetPort: 9000
          protocol: TCP
      selector:
        app.kubernetes.io/name: ingress-nginx
        app.kubernetes.io/part-of: ingress-nginx

[https_www.nginx.com_resources_admin-guide_proxy-protocol]: https://www.nginx.com/resources/admin-guide/proxy-protocol
[UDP Load Balancing]: https://www.nginx.com/blog/announcing-udp-load-balancing/